浙江省湖州市A(H1N1)pdm09流感病毒耐药基因的变异分析

Analysis of drug resistance gene variation of influenza A(H1N1)pdm09 virus in Huzhou City,Zhejiang Province

【目的】了解浙江省湖州市2023年A(H1N1) pdm09流感流行株耐药基因变异和遗传进化特征。【方法】收集2家流感监测医院的呼吸道标本进行A(H1N1) pdm09流感病毒核酸检测,阳性标本接种MDCK细胞进行流感病毒分离和测序。应用DNA Star 7.1软件和Mega4.0软件对神经氨酸酶(NA)基因酶活性位点和M2离子通道蛋白(M2蛋白)与耐药相关的氨基酸位点进行分析。【结果】分离株与疫苗株的NA基因核苷酸同源性范围为98.87%~99.22%,氨基酸同源性范围为98.94%~99.36%。M基因核苷酸同源性范围为99.07%~99.85%,氨基酸同源性范围为99.02%~99.94%,分离株和疫苗株同属于6B.1A.5a.2a进化分支。NA基因酶活性中心关键位点氨基酸仍高度保守,与NA抑制剂耐药相关的9个关键氨基酸位点无变异,但部分流行株非酶活性位点发生一些变异。分离株M2蛋白与耐药相关的5个氨基酸位点未发生替换,但第31位氨基酸由丝氨酸变为天冬酰胺。【结论】2023年湖州市A(H1N1) pdm09流行株与世界卫生组织(WHO)推荐的2023—2024年疫苗株有较高的同源性。所有流行株均对金刚烷胺类药物耐药。

[Objective]To investigate the mutation and genetic evolution of drug resistance gene of A(H1N1)pdm09 influenza pandemic strain in 2023 in Huzhou City,Zhejiang Province.[Methods]Respiratory tract specimens from 2 influenza monitoring hospitals were collected for A(H1N1)pdm09 influenza virus nucleic acid detection.Positive specimens were inoculated with MDCK cells for influenza virus isolation and sequencing.DNA Star 7.1 software and Mega 4.0 software were used to analyze the neuraminidase(NA)enzyme active site and the amino acid sites related to drug resistance in M2 protein.[Results]Nucleotide homology and amino acid homology of NA between the isolated and the vaccine strains were 98.87%‒99.22%and 98.94%‒99.36%,respectively.The nucleotide homology range of M gene was 99.07%to 99.85%,and the amino acid homology range was 99.02%‒99.94%.The isolates and vaccine strains belong to the evolutionary clades of 6B.1A.5a.2a.The amino acids at the key sites of the enzyme activity center of NA were still highly conserved,and the 9 key amino acid sites related to NA inhibitor resistance did not change,but some mutations occurred at the non-enzyme active sites in some popular strains.The 5 amino acid sites related to drug resistance of M2 protein were not replaced,but the 31st amino acid sites changed from serine to asparagine.[Conclusion]The A(H1N1)pdm09 pandemic strain in Huzhou in 2023 has high homology with the 2023‒2024 vaccine strain recommended by WHO.All endemic strains are resistant to amantadines.